* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

*::after {
    box-sizing: border-box;
}

*::before {
    box-sizing: border-box;
}

body {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.code-box {
    flex: 1;
    height: 50%;
    padding: 10px;
}

.page-box {
    flex: 1;
    height: 50%;
}

#code {
    overflow: hidden;
    height: 100%;
    position: relative;
}


/* 按钮区域 */

.button {
    position: absolute;
    top: 20px;
    right: 15px;
    display: flex;
    flex-direction: column;
    width: 60px;
}

.button .slow {
    margin-top: 15px;
}

.button .middle {
    margin-top: 15px;
}

.button .fast {
    margin-top: 15px;
}